Height adjustment mechanism for swivel chairs

ABSTRACT

A support portion includes a sleeve having slots formed therethrough for gaining access to the interior of the sleeve. A threaded screw portion has the upper end thereof interconnected with a seat support and is rotatably supported within the sleeve. A nut is threaded on the screw portion and includes a laterally extending projection adapted to engage a member extending through the hole in the sleeve to prevent rotation of the nut upon rotation of the screw portion. A further screw is supported by the support portion for preventing disassembly of the mechanism.

United States Patent Textoris 1 Feb. 15, 1972 [54] HEIGHT ADJUSTMENTMECHANISM FOR SWIVEL CHAIRS [72] Inventor: Melvin A. Textoris,Struthers, Ohio [73] Assignee: The General Fireproofing Company,

Youngstown, Ohio [22] Filed: Jan. 28, 1970 21 Appl. No.: 6,352

[52] US. Cl ..248/406, 287/58 CT [51] Int. Cl. ..Fl6m 11/00 [58] Fieldof Search ..248/i88.4, 405, 406; 287/58 CT, 61

[56] References Cited UNITED STATES PATENTS 437,188 9/1890 Franklin..248/406 593,059 1 1/ 1897 Sheriffs et al. .....248/406 1,817,5598/1931 l-larter ..248/406 X 1,973,948 9/1934 Fogelstrom ..248/l88.4

FOREIGN PATENTS OR APPLICATIONS 1,045,510 10/ l 966 Great Britain..248/405 Primary Examiner-William H. Schultz Attorney-Emory L. Grofiand Emory L. Grofi", Jr.

[5 7] ABSTRACT A support portion includes a sleeve having slots formedtherethrough for gaining access to the interior of the sleeve. Athreaded screw portion has the upper end thereof interconnected with aseat support and is rotatably supported within the sleeve. A nut isthreaded on the screw portion and includes a laterally extendingprojection adapted to engage a member extending through the hole in thesleeve to prevent rotation of the nut upon rotation of the screwportion. A further screw is supported by the support portion forpreventing disassembly of the mechanism.

6 Claims, 4 Drawing Figures PATENFEFEB 16 1972 mvsn'mn MELVIN A.TEXTORI3ATTOR N EYS HEIGHT ADJUSTMENT MECHANISM FOR SWIVEL CHAIRS BACKGROUND OFTHE INVENTION The present invention relates to mechanism for adjustingthe height of the seat support in an associated seat of a swivel chair.

ln swivel chairs, it is, of course, necessary to provide a supportmechanism which normally allows free swiveling movement of the seatwhile at the same time it permits raising and lowering of the seat toadjust the height thereof to accommodate persons of different size.

Various constructions have been provided in the prior art for permittingheight adjustment of swivel chairs, and such mechanisms are often ofexcessively complex and bulky construction, and furthermore, suffer fromthe disadvantage that they are difficult to adjust.

It is accordingly an objective of the present invention to provide aheight adjustment mechanism for swivel chairs which is quite simple andinexpensive in construction and additionally which enables heightadjustment to be made in a most simple and effective manner with aminimum of effort and without requiring the swivel chair to be turnedupside down to gain access to the adjustment mechanism as is oftenrequired with prior art constructions.

SUMMARY OF THE INVENTION A support portion includes a sleeve having apair of diametrically opposite slots formed therein for gaining accessto the sleeve. A stop means in the form of a screw is also threadedwithin the sleeve and extends inwardly thereof so as to preventdisassembly of the mechanism until such disassembly is desired.

A screw portion is rotatably supported within the sleeve and the upperend thereof is interconnected with a seat support upon which the seat ofthe swivel chair is mounted. A screw portion has threads formed on theouter surface thereof, and nut means is threaded on the screw portion.

The nut means includes a laterally extending projection which is adaptedto engage a member extending through one of the slots formed in thesleeve whereby the nut means can be held against rotation while the seatand seat support are rotated thereby causing rotation of theinterconnected screw portion. As the screw portion rotates with respectto the nut means which is held against rotation, the screw portion willmove axially so as to raise or lower the seat depending upon thedirection of relative rotation between the screw portion and the nutmeans.

The seat support and associated seat are ordinarily mounted for freeswiveling movement, and when it is desired to make a height adjustment,any suitable member such as a coin, the end of a standard Allen wrenchor any other suitable type of wrench or tool may be inserted through oneof the slots formed in the sleeve of the support portion for engagingthe projection on the nut means to hold the nut against rotation. Whenthe nut is being so held, the seat and seat support can be rotated inthe appropriate direction so as to cause the desired height adjustment.This operation can be carried out without turning the chair upside downand access can readily be gained to the nut means for producing suchadjustment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a vertical section throughthe height adjustment mechanism of a swivel chair according to thepresent invention with portions thereof being broken away;

FIG. 2 is a sectional view on an enlarged scale taken substantiallyalong line 22 of FIG. 1 looking in the direction of the arrows;

FIG. 3 is a sectional view taken substantially along line 3-3 of FIG. 1looking in the direction of the arrows; and,

FIG. 4 is a top perspective view illustrating the height adjustmentmechanism with the seat and seat support removed therefrom.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingswherein like reference characters designate corresponding partsthroughout the several views, four substantially equally spaced legportions 10, 12, I4 and 16 are provided, these leg portions being of anysuitable relatively conventional construction and having the usualcaster mechanisms mounted at the outer ends thereof. The inner ends ofthe leg portions are rigidly secured as by welding to a support sleeve20 of generally cylindrical crosssectional configuration. Sleeve 20 maybe formed of a suitable strong material such as steel tubing.

A tubular hub 24 having a central bore 26 formed therethrough is fittedwithin sleeve 20 and is welded thereto. Hub 24 may be formed for exampleof cold rolled steel. An antifriction liner 30 of tubular constructionis disposed within the bore 26 formed through the hub and has aperipherally extending radially outwardly directed flange 32 at theupper end thereof which rests on the upper edge of hub 24. Liner 30 maybe formed of any suitable antifriction material such as Delrin or thelike. a

A screw portion 40 comprises an elongated generally cylindrical memberhaving threads 42 formed on the outer surface thereof and receivedwithin the central bore defined through liner 30. The upper end 44 ofthe screw portion is of reduced dimension and is press fitted within anextension means or post 46 which may also be formed of cold rolledsteel. A generally cup-shaped bearing 48 formed of a suitableantifriction material such as nylon is disposed about the lower end ofextension means 46 and is disposed between the extension means and thesurrounding sleeve.

The upper end 50 of the extension means is of reduced dimension and fitsthrough a hole provided in a plate 52 and is rigidly secured thereto asby welding. Plate 52 forms the lower part of a conventional seat support54 which supports an associated seat indicated by phantom line 56 of theswivel chair.

An annular washer 60 is disposed in surrounding relationship to thescrew portion and is seated on the flange 32 at the upper end of theliner. A nut 62 has a threaded bore formed therethrough which receivesthe threaded screw portion, this nut being seated on washer 60. Nut 62includes a laterally extending projection 64 which is adapted to beengaged by a suitable member for holding the nut against rotation.

In order to gain access to the nut and the projection formed thereon, apair of diametrically oppositely disposed elongated slots 70 and 72 areprovided. These slots are adapted to receive any suitable member such asa coin, a wrench or any other suitable tool for engaging the projectionon the nut to hold the nut against rotation. These slots are, of course,disposed in portions of the sleeve intermediate the associated legportions, and as seen most clearly in FIG. 3, slot 70 is disposedbetween leg portions 10 and 14, and slot 72 is disposed between legportions 12 and 16.

Sleeve 20 is also provided with a further threaded hole disposeddirectly above slot 72, a screw being threaded into this hole andextending inwardly so as to be disposed in overlying relationship to aportion of nut 62. This screw prevents the mechanism from beinginadvertently disassembled if one should lift the seat support and seatwith respect to the leg portions. When it is desired to disassemble themechanism, screw 80 may be removed whereupon the seat and seat supportalong with the screw portion and nut means may be lifted out of thesupport portion.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof,

the present embodiment is therefore illustrative and not V restrictive.

I claim:

1. Height adjustment mechanism for a swivel chair including a seatsupport disposed above a leg structure, comprising, a tubular sleevefixedly attached to said leg structure and extending upwardly toward thebottom of said seat support, a longitudinally extending tubular hubfixedly mounted within the lower portion of said sleeve and having anantifriction liner substantially overlying its inner periphery, a postattached to the bottom of said seat support and extending downwardlytherefrom into said tubular sleeve, radial bearing means carried by thelower portion of said post and slidably engaging said sleeve, alongitudinal screw element enveloped within said sleeve and having itslower portion slidably fitted within said antifriction liner and itsupper end fixedly attached to the lower portion of said post within saidsleeve, a nut engaging said screw element intermediate the bottom ofsaid post and the top of said hub within said sleeve, thrust bearingmeans intermediate said nut and the top of said hub, and access meansthrough said sleeve juxtaposed said nut to permit insertion of suitablemeans engageable with said nut to prevent rotation thereof wherebysubsequent rotation of said seat support turns said post and screwelement to vary the height thereof relative to said nut and the legstructure.

means comprises a screw removably mounted through said sleeve.

5. Mechanism as defined in claim I, wherein said thrust bearing meansincludes a flat washer.

6. Mechanism as defined in claim I, wherein said thrust bearing meansincludes an extension of said liner radially projecting over the topportion of said hub.

i U i i

1. Height adjustment mechanism for a swivel chair including a seatsupport disposed above a leg structure, comprising, a tubular sleevefixedly attached to said leg structure and extending upwardly toward thebottom of said seat support, a longitudinally extending tubular hubfixedly mounted within the lower portion of said sleeve and having anantifriction liner substantially overlying its inner periphery, a postattached to the bottom of said seat support and extending downwardlytherefrom into said tubular sleeve, radial bearing means carried by thelower portion of said post and slidably engaging said sleeve, alongitudinal screw element enveloped within said sleeve and having itslower portion slidably fitted within said antifriction liner and itsupper end fixedly attached to the lower portion of said post within saidsleeve, a nut engaging said screw element intermediate the bottom ofsaid post and the top of said hub within said sleeve, thrust bearingmeans intermediate said nut and the top of said hub, and access meansthrough said sleeve juxtaposed said nut to permit insertion of suitablemeans engageable with said nut to prevent rotation thereof wherebysubsequent rotation of said seat support turns said post and screwelement to vary the height thereof relative to said nut and the legstructure.
 2. Mechanism as defined in claim 1, including a projection onsaid nut extending laterally outwardly therefrom for engagement by amember inserted through said access means.
 3. Mechanism as defined inclaim 1, including stop means projecting inwardly between said nut andsaid post for preventing unwanted disassembly of the mechanism. 4.Mechanism as defined in claim 3, wherein said stop means comprises ascrew removably mounted through said sleeve.
 5. Mechanism as defined inclaim 1, wherein said thrust bearing means includes a flat washer. 6.Mechanism as defined in claim 1, wherein said thrust bearing meansincludes an extension of said liner radially projecting over the topportion of said hub.